• Geophysics and Geophysical Exploration
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• v.13 no.1
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• pp.31-39
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• 2010

The goal of automatic velocity analysis is to extract accurate velocity from voluminous seismic data with efficiency. In this study, we developed an efficient automatic velocity analysis algorithm by using bootstrapped differential semblance (BDS) and Monte Carlo inversion. To estimate more accurate results from automatic velocity analysis, the algorithm we have developed uses BDS, which provides a higher velocity resolution than conventional semblance, as a coherency estimator. In addition, our proposed automatic velocity analysis module is performed with a conditional initial velocity determination step that leads to enhanced efficiency in running time of the module. A new optional root mean square (RMS) velocity constraint, which prevents picking false peaks, is used. The developed automatic velocity analysis module was tested on a synthetic dataset and a marine field dataset from the East Sea, Korea. The stacked sections made using velocity results from our algorithm showed coherent events and improved the quality of the normal moveout-correction result. Moreover, since our algorithm finds interval velocity ($\nu_{int}$) first with interval velocity constraints and then calculates a RMS velocity function from the interval velocity, we can estimate geologically reasonable interval velocities. Boundaries of interval velocities also match well with reflection events in the common midpoint stacked sections.

• Journal of Environmental Health Sciences
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• v.21 no.3
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• pp.38-47
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• 1995

The Bioconcentration factor (BCF) is used as an important criterion in the risk assessment of environmental contaminants. Also it can be used as indicator of biomagnification of environmentally hazardous chemicals through food-chain as well as a tool for ranking the bioconcentration potential of the chemicals in the environment. This paper reports the measured BCF value on Chlorothalonil in Carassius auratus(goldfish), under steady state, and examined correlation between the BCF value and the partition coefficient or acute toxicity or physicochemical properties. Carassius auratus(goldfish) was chosen as test organism and test period were 3-day, 5-day. Experimental concentrations were 0.005, 0.01 and 0.05 ppm. Chlorothalonil in fish tissue and in test water were extracted with n-hexane and acetonitrile. GC-ECD was used to detecting and quantitating of Chlorothalonil. Partition coefficient was determined by stir-flask method. $LC_{50}$ was determined on Chlorothalonil. Carbaryl and BPMC. The obtained results were as follows. 1. It was possible to determine short term BCFs of Chlorothalonil through relatively simple procedure in environmental concentrations. 2. $BF_3$ of Chlorothalonil in concentration of 0.005, 0.01 and 0.05 ppm were 2.1866$\pm$0.23446, 3.5269$\pm$0.23517, 10.2045$\pm$0.18053 and BCFs were 6.6543$\pm$0.55257, 6.9774$\pm$0.02500, 23.4576$\pm$2.06884, respectively. 3. Chlorothalonil concentration in fish extract and BCFs of Chlorothalonil were increased as increasing test concentration and prolonging test period. 4. Fate of test-water concentration on Chlorothalonil was greater than that of control-water con-centration. It is considered that greater fate of test-water concentration on Chlorothalonil is due to hydrolyzing nitrile group under the mild condition and substituting chloro group by some aromatic compounds in test water. 5. Determined logP of Chlorothalonil was 2.80. And determined $LC_{50}$ of Chlorothalonil in time of 24, 48, 72 and 96 hr were 0.1684, 0.1402, 0.1400, 0.1352(mg/l) respectively. And $LC_{50}$ of Carbaryl in above times were 19.918, 18.635, 18.466, 18.12(mg/l) respectively. $LC_{50}$ of BPMC were 10.248, 9.166, 9.087, 8.921(mg/l) respectively. 6. It is suggested that the BCF of Carbamates depend on partition coefficients. But BCF of Chlorothalonil, organochlorine pesticide, would be strongly influenced by steric, electronic effect of substituents than partition coefficient.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.2
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• pp.113-125
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• 2012

This research is aimed at evaluating the land surface characterization of KOMPSAT-3A middle infrared (MIR) data. Airborne Hyperspectral Scanner (AHS) data, which has MIR bands with high spatial resolution, were used to assess land surface temperature (LST) retrieval and classification accuracy of MIR bands. Firstly, LST values for daytime and nighttime, which were calculated with AHS thermal infrared (TIR) bands, were compared to digital number of AHS MIR bands. The determination coefficient of AHS band 68 (center wavelength $4.64{\mu}m$) was over 0.74, and was higher than other MIR bands. Secondly, The land cover maps were generated by unsupervised classification methods using the AHS MIR bands. Each class of land cover maps for daytime, such as water, trees, green grass, roads, roofs, was distinguished well. But some classes of land cover maps for nighttime, such as trees versus green grass, roads versus roofs, were not separated. The image classification using the difference images between daytime AHS MIR bands and nighttime AHS MIR bands were conducted to enhance the discrimination ability of land surface for AHS MIR imagery. The classification accuracy of the land cover map for zone 1 and zone 2 was 67.5%, 64.3%, respectively. It was improved by 10% compared to land cover map of daytime AHS MIR bands and night AHS MIR bands. Consequently, new algorithm based on land surface characteristics is required for temperature retrieval of high resolution MIR imagery, and the difference images between daytime and nighttime was considered to enhance the ability of land surface characterization using high resolution MIR data.

• Journal of Wetlands Research
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• v.17 no.3
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• pp.251-263
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• 2015

This study suggested a novel approach of estimating the optimal probability density function (OPDF) of the annual maximum rainfall time series (AMRT) combining the L-moment ratio diagram and the geographical information system. This study also reported several interesting geographical characteristics of the AMRT in Korea. To achieve this purpose, this study determined the OPDF of the AMRT with the duration of 1-, 3-, 6-, 12-, and 24-hours using the method of L-moment ratio diagram for each of the 67 rain gages in Korea. Then, a map with the Thiessen polygons of the 67 rain gages colored differently according the different type of the OPDF, was produced to analyze the spatial trend of the OPDF. In addition, this study produced the color maps which show the fitness of a given probability density function to represent the AMRT. The study found that (1) both L-skewness and L-kurtosis of the AMRT have clear geographical trends, which means that the extreme rainfall events are highly influenced by geography; (2) the impact of the altitude on these two rainfall statistics is greater for the mountaneous region than for the non-mountaneous region. In the mountaneous region, the areas with higher altitude are more likely to experience the less-frequent and strong rainfall events than the areas with lower altitude; (3) The most representative OPDFs of Korea except for the Southern edge are Generalized Extreme Value distribution and the Generalized Logistic distribution. The AMRT of southern edge of Korea was best represented by the Generalized Pareto distribution.

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.727-735
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• 2012

Recently, a high-strength strand of 2400 MPa was developed using domestic technologies. In 2011, KS D 7002 was revised to cover the newly developed high-strength strands to support their practical usage. Presently, however, discussions and evaluations are not sufficient on the mechanical properties of the strands and their performance in structural members. Also, there were no detailed reviews on the need to revise the current design code for practical use of the high-strength strands. In this study, flexural behavior of a member with the high-strength strands was estimated through sectional analysis and a review and comparison of the domestic and foreign design codes were conducted considering the analysis results. Also, the need for the revision of the design code was discussed. Such discussion especially focused on the estimation of the stress in strand, which related with various issues such as determination methods for yield point of strands, time-dependent loss of prestressing force, estimation of stress in strand at member failure, and net strain limit for ductile failure of member. The discussion revealed that some parts in the design code need a revision and the further studies are required.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.3
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• pp.395-402
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• 2018

Objective: An experiment was conducted to evaluate effects of inclusion level of palm kernel meal (PKM) and adaptation duration on the digestible energy (DE) and apparent total tract digestibility (ATTD) of chemical constituents in diets fed to growing-finishing pigs. Methods: Thirty crossbred barrows ($Duroc{\times}Landrace{\times}Large\;White$) with an average initial body weight of $85.0{\pm}2.1kg$ were fed 5 diets in a completely randomized design. The diets included a corn-soybean meal basal diet and 4 additional diets in which corn and soybean meal were partly replaced by 10%, 20%, 30%, or 40% PKM. After 7 d of adaptation to the experimental diets, feces were collected from d 8 to 12, d 15 to 19, d 22 to 26, and d 29 to 33, respectively. Results: The DE and ATTD of gross energy (GE), dry matter (DM), ash, organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP) in diets decreased linearly as the dietary PKM increased within each adaptation duration (p<0.01). Diet containing 19.5% PKM had less DE value and ATTD of all detected items compared with other diets when fed to pigs for 14 days (p<0.05). The ATTD of CP in PKM calculated by 19.5% and 39.0% linearly increased as adaptation duration prolonged from 7 to 28 days (p<0 .01). Conclusion: Inclusion level of PKM and adaptation duration had an interactive effect on DE and the ATTD of GE, DM, OM, and CP (p<0.01 or 0.05) but ash, NDF, and ADF in diet (p>0.05). Considering a stable determination, 21 days of adaptation to a diet containing 19.5% PKM is needed in pigs and a longer adaptation time is recommended as dietary PKM increases.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.463-471
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• 2011

A novel $N_2O_2$ Schiff base ligand, N,N'-bis(4-methoxysalicylidene)phenylendiamine(4-$CH_3O$-Salphen), has been synthesized. It has been revealed that the compound is very useful for the spectrophotometric quantification of Fe(II) and Fe(III) ions in aqueous solutions, such as mineral water, hot spring water, sea water, and waste water. The optimum conditions for the quantitative analysis are the followings; [4-$CH_3O$-Salphen]=$4.0{\times}10^{-4}\;M$, DMF/$H_2O$=70/30(v/v), pH=3.4~3.8, T= at $55^{\circ}C$, and prereaction time=1.0 hr. The sample of single valence state was prepared by the preliminary oxidation or reduction using $H_2O_2$ ($5.0{\times}10^{-4}\;M$) and $NH_2OH{\cdot}HCl$ ($5.0{\times}10^{-4}\;M$). The quantitative analyses of Fe(II) and Fe(III) ion were performed by measuring the absorbance at 434 nm and 456 nm, respectively. The estimated mean values agreed well with the standard values within the range of 2.00~6.90%. The limit of detection was 27.9 ng/mL for Fe(II) and 55.8 ng/mL for Fe(III).

• Computational Structural Engineering
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• v.6 no.3
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• pp.67-80
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• 1993

This paper presents the results of an analytical study to evaluate the inelastic seismic response characteristics of multistory building structures, the effects of gravity load on the seismic responses and its implications on the earthquake resistant design. Static analyses for incremental lateral force and nonlinear dynamic analyses for earthquake motions were performed to evaluate the seismic response of example multistory building structures. Most of considerations are placed on the distribution of inelastic responses over the height of the structure. When an earthquake occurs, bending moment demand is increased considerably from the top to the bottom of multistory structures, so that differences between bending moment demands and supplies are greater in lower floos of multistory structures. As a result, for building structures designed by the current earthquake resistant design procedure, inelastic deformations for earthquake ground motions do not distribute uniformly over the height of structures and those are induced mainly in bottom floors. In addition, gravity load considerded in design procedure tends to cause much larger damages in lower floors. From the point of view of seismic responses, gravity load affects the initial yield time of griders in earlier stage of strong earthquakes and results in different inelastic responses among the plastic hinges that form in the girders of a same floor. However, gravity load moments at beam ends are gradually reduced and finally fully relaxed after a structure experiences some inelastic excursions as a ground motion is getting stronger. Reduction of gravity load moment results in much increased structural damages in lower floors building structures. The implications of the effects of gravity load for seismic design of multistory building structures are to reduce the contributions of gravity load and to increased those of seismic load in determination of flexual strength for girders and columns.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.3
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• pp.93-101
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• 2017

The distribution of inter-annual variation in temperature would help evaluate the likelihood of a climatic risk and assess suitable zones of crops under climate change. In this study, we evaluated two methods to estimate the standard deviation of temperature in the areas where weather information is limited. We calculated the monthly standard deviation of temperature by collecting temperature at 0600 and 1500 local standard time from 10 automated weather stations (AWS). These weather stations were installed in the range of 8 to 1,073m above sea level within a mountainous catchment for 2011-2015. The observed values were compared with estimates, which were calculated using a geospatial correction scheme to derive the site-specific temperature. Those estimates explained 88 and 86% of the temperature variations at 0600 and 1500 LST, respectively. However, it often underestimated the temperatures. In the spring and fall, it tended to had different variance (e.g., increasing or decreasing pattern) from lower to higher elevation with the observed values. A regression analysis was also conducted to quantify the relationship between the standard deviation in temperature and the topography. The regression equation explained a relatively large variation of the monthly standard deviation when lapse-rate corrected temperature, basic topographical variables (e.g., slope, and aspect) and topographical variables related to temperature (e.g., thermal belt, cold air drainage, and brightness index) were used. The coefficient of determination for the regression analysis ranged between 0.46 and 0.98. It was expected that the regression model could account for 70% of the spatial variation of the standard deviation when the monthly standard deviation was predicted by using the minimum-maximum effective range of topographical variables for the area.

• Journal of Conservation Science
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• v.9 no.1
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• pp.40-47
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• 2000

Dimension stability was examined after PEG pretreatment and post freeze-drying treatment in order to determine the PEG(#3350) concentration and solvent for pre-treatment of freeze-drying of highly-degraded waterlogged ash woods(Fraxinus spp.; ca. 5,700 BP) excavated from peat lands at Pyungtack, Kyounggi-do. At the low concentration (<30-40%) of PEG soaking in both water and t-butanol, the weight increases abruptly, but at high concentration (>50%) gradually, consequently, taking longer treatment time. PEG loading was higher in t-butanol solution than in water. However, the best dimesional stability was obtained from freeze-drying after lower PEG solution (40% in water) soaking. Low dimensional stability, found in the samples treated with higher PEG solutions (60%-70% in t-butanol), might come from incomplete freezing and excess PEG absorbing moisture. The samples air-dried after 70% PEG treatment had collapse defects. In conclusion, the use of low concentration (about 40% in water) PEG solution was the most suitable pretreatment for freeze drying of highly-degraded waterlogged ash woods.